In the field of treating spinal disorders (e.g., a surgery for realigning misaligned vertebrae), an operator implants one or several bone attachment members such as bone screws into the misaligned vertebrae, and re-aligns the vertebrae using handles attached to the bone attachment members.
A distance between the bone attachment members can be set by a distractor device disposed between distal ends of the bone attachment members. The distractor device is adjusted to increase or decrease the distance between the bone attachment members to aid the operator in adjusting the positioning of the vertebrae. Distal ends of the handles may be contained within a linkage element adapted to stabilize the distal handle ends during distraction (or compression) while allowing the operator to manipulate the positioning of the handles with the bone attachment members by pivotal and/or rotational movement.
German utility model G 87 12 943 describes a surgical assembly having bone attachment members disposed on handles and a distractor device disposed near proximal ends of the handles. Distal ends of the handles can be inserted into holes in an elongated linkage element such that the linkage element is disposed around the distal ends. Several holes are located along the linkage element, so that the operator can choose the desired distance between the two handles by inserting the distal handle ends of the handles into the holes having a desired separation distance. The handles are pivotable and rotatable within the holes of the linkage element.
U.S. patent application No. 2009/0062858 describes a further surgical assembly having bone attachment members disposed on proximal ends of two handles, a distractor device and a linkage element receiving distal ball ends of the handles. The linkage element comprises two ball cups for receiving the distal ball ends of the handles such that the handles may be pivoted and rotated. Additionally, one of the ball cups may be moved axially along the linkage element so that an operator can change an axial distance between the distal ends of the handles.
In the surgical assemblies of the prior art, the operator positions the handles to obtain an approximated alignment of the vertebrae. The operator then checks the alignment of the vertebrae with the selected positioning of the bone attachment members by taking and analysing an X-ray image of the realigned vertebrae. Based on the X-ray image, the operator can confirm a proper alignment of the vertebrae, or may make further adjustments as necessary.
Because X-ray exposure is a known health risk, and because an operator may have to take X-ray images frequently during the realignment procedure and during successive procedures, the operator desires to leave the operating room when the X-ray images are taken. However, because the surgical assemblies of the prior art are designed to allow the operator to manipulate the handles by pivoting or rotating movements, the positioning of the assembly is potentially unstable. Therefore, the operator may be reluctant to release his grip on the handles in order to be able to leave the room during the X-ray imaging procedure.
Further, when the operator releases his grip on the handles, the surgical assembly may move, requiring the operator to reposition the assembly. This may be time consuming and inefficient for the operator, and may cause additional damage to body tissue and pain for the patient. Still further, the additional time consumed in readjusting the assembly that has moved when the operator releases his grip may cause a lengthened surgery time, thus causing an increased health risk to the patient.